Technical Field
The invention relates generally to the field of systems and methods for detecting gas leaks.
Description of the Related Art
The leakage of natural gas from wells, associated equipment, pipelines, distribution networks, and other points leads to a loss of between approximately 1.5% to 8% or more of the total natural gas extracted from the ground. Additionally, the leakage may have a significant safety and environmental impact. Therefore, there is a need for governments, organizations, and natural gas companies to periodically inspect potential leak sites and detect any leakage.
Traditionally, fugitive emission detection in gas fields is done primarily with forward-looking infrared cameras (FLIRs). This camera provides video imagery that is sensitive to the temperature differences between the leaking natural gas and the surrounding atmosphere. This camera is typically hand-held and shows a real-time screen much like a consumer digital camera. The result is entirely qualitative and relies on the observation and judgment of a human operator. For example, methane leaks appear as a smoke-like vapor emitting from the leak site.
In cases where a more quantitative measurement is desired, measurements are taken according to the Environmental Protection Agency's Method 21—Determination of Volatile Organic Compound Leaks. Method 21 is an official standard by which leaks can be quantitatively measured and shown to be in or out of compliance with any regulation. Method 21 provides the requisite calibration accuracy, response time, and sensitivity for any device intended to provide regulatory compliance measurements. Typically, Method 21 instrumentation records the concentration of various volatile organic compounds by using a probe with a single-end opening to directly sample the air in proximity to a leak site.
These known leak detection systems and methods suffer from a number of drawbacks and deficiencies. First, they are labor intensive and costly. Each potential leak site must be physically visited by at least one test technician. The technician must then systematically examine the entire surface of the site with the leak detection device. Depending on the size of the site in question, this can require from an hour to several hours or days of the technician's labor. With many organizations having hundreds or thousands of sites to examine, many technicians and leak detection devices are required in order to perform periodic (e.g., monthly) inspections of every site. However, because of this high cost, most sites are currently not inspected on a periodic basis. Nevertheless, new regulations may require a higher frequency of inspection, which may represent a significant monetary burden in testing.
Second, these systems and methods are subject to variation in a technician's experience and performance, and also to the technician's error. Different technicians may apply different levels of thoroughness in the inspection of the site, leading to different outcomes.
Third, these solutions are not scalable. As the number of sites and the visiting frequency per site increases, the number of technicians and leak detection devices required also increases proportionally. The result is that the cost of monitoring gas leakage via these systems and methods grows rapidly.
Therefore, there is a need in the art to provide systems and methods for improving the detection of gas leaks. Accordingly, it is desirable to provide methods and systems that overcome these and other deficiencies of the related art.